Hold-up alarm



Sept. 22, 1936. J. H. DERBY ET Al.

HOLD-UP ALARM Filed Nov. 14, 1933 2 Sheets-Sheet l INVENTORS Jamv H Omar ADOAPH/Z F9057 QWW W ATTORNEYS Sept. 22, 1936. J. H. DERBY ET AL HOLD-UP ALARM Filed Nov. 14, 1933 2 Sheets-Sheet 2 INVENTORS .[OHN H. DfPBY ADOLPH M. F 057 B gzwqigq ATTORNEYS J/ J {if Patented Sept. 22, 1936 PATENT OFFICE HOLD-UP ALARM John H. Derby, Scarsdale, and Adolph M. Frost, Arverne, N. Y" said Frost assignor to said Derby Application November 14, 1933, Serial No. 697,889

4 Claims.

This invention relates to means for quickly and quietly effecting the closing of an alarm circuit and for maintaining it in closed condition for a sufficient length of time to insure the giving of an alarm, and is particularly intended for transmitting alarms in cases of holdup or attempted,

robbery of banks, cashiers offices or other places where substantial sums of money are kept. In such holdups or attempted robberies the bandits or robbers usually employ firearms to intimidate the tellers, cashiers or other employees or ofiicials of the institution in which the hold up or attempted robbery occurs.

The success of a robbery or holdup depends usually upon its being carried out in a very short space of time. As a result of the necessity for hurry to prevent interference with their plans, the robbers or highwaymen are under a very severe nervous tension which is apt to make them quick on the trigger. Furthermore, the knowledge of this fact by the employees of the institution being robbed and the knowledge that efforts to frustrate the holdup or robbery must be speeded puts the employees also under a very severe nervous tension. It is, therefore, important that any provision for transmitting an alarm in 7 cases of holdup or attempted robbery be so arranged and the transmitting means be so constructed and operated that not only will it not attract the attention of the robber when the alarm signal is sent, but also it will surely function.

The present invention is an improvement upon holdup aiarms of the type described and claimed in the copencling application of John H. Derby,

' Serial No. 537, 527, filed May 15, 1931. As pointed out in the statement of invention of said co-pending application, the holdup alarm of said application is so designed and constructed that it can be operated by a movement of the toe of the foot of the person who is being held up which is so slight that it will not affect the position of the rest of the body and will thus not be noticed by the bandit or robber, and yet it is so designed that it is substantially free from liability to accidental operation. Moreover, by the use of a mercury switch and of means for deadening the sound of the other movable parts, the operation of the device is rendered so nearly noiseless that this element of danger from the operation of an alarm switch is substantially removed.

When operated, the switch of the co-pending application is locked in its circuit-closing position against movement to open position by pressure on those parts extending outside the housing and it is housed in a casing which is so locked that the switch cannot readily be restored to open circuit position because of the necessity for first obtaining a key to the casing. This insures that the signal will be transmitted for a length of time suiiicient to attract attention.

An object of the present invention is to effect improvements in the alarm switch of said copending application in those respects which have to do with its sure functioning. To this end one aim of the invention is so to multiply the tilting movement of the mercury switch, which is effected through operation of the foot-operated lever, as to avoid any possibility that the mercury will not be moved from its non-circuit-closing position to the position in which it bridges the circuit terminals. The invention aims further so to relate the means which retains the switch in open position to the means which looks the switch in its closed position that the effort required to overcome the retaining means, that is, the pressure upon the foot-operated lever, will be suflicient to insure carrying the switch to the circuit-closing and switch-locking position as the retaining means lets go. The invention also aims to aid and accelerate the movement to closed position by means of the stored-up energy of a spring which begins to operate as soon as the retaining means has let go.

An important feature of the invention is the utilization of a single spring member as a part of the means for retaining the switch in open position, as the means for accelerating its movement to closed position and as a part of the means for locking it in closed position.

Another, important feature of the invention is the utilization of a connection from the manually operated means to the mercury switch, which is in the nature of an inverted toggle having fixed terminals and a lost motion connection at its knee joint, to effect, by means of a small angular movement of the manually operated means, such a multiplication of the angular movement of the mercury switch as to swing it from one angular position of substantially 37 to the horizontal, in which the mercury is maintained at that end of the switch tube remote from the circuit terminals, to another 37 inclination to the horizontal in which the mercury is maintained in that end of the tube in which the circuit terminals are located.

It will be understood, of course, that the invention is not restricted to a 37 tilt of the mercury switch and that such multiplication of the angular movement of the mercury tube may be effected as will insure its being so positioned at each end of its travel that the mercury will be definitely positioned in one end or the other, as desired.

Other objects and important features of the invention will appear from the following description and claims when considered in connection with the accompanying drawings, in which Figure 1 is a plan view of an alarm switch embodying the present invention, the cover of the casing being removed to show the construction and arrangement of the interior mechanism;

Figure 2 is a section on the line 2--2 of Figure 1, the cover being inposition: in this figure;

Figure 3 is a detail section through the connection between the bellcrank lever that is operatedby the foot and the rocking lever that carries the mercury switch;

Figure 4 is a section on the ure 2;

Figure 5 is a section on'the line '55 of Figure 2, and

Figure 6 is a circuit diagram;

The illustrated alarm signal transmitting device, like that of the co-pending application above identified, ,is of the type which is particularly designed for banks, cashiers cages and similar places where theone' who receives or pays out money usually stands or sits at a raised shelf or desk and is prbvided with a foot rest on which one or both feet may be placed, according as the line- 44 of Figemployee is standing or sitting. In the i1lustra-- tive preferred embodiment of the invention the circuit-closing mechanism is associated with and is preferably partly enclosed within a foot rest which is especially designed for carrying the signal-transmitting means. This foot rest is made in the" form of a housing 2, within which the circuit-closing means and the means for yield- 1 ingly holding it in its open condition and positively holding itin its closed condition are located. The housing 2 is supported above the floor by legs 4 formed by downward extensions of the lateral or end walls of the housing.

The housing 2 is provided with a cover 6, so inclined as" to form a convenient foot rest, the cover 6 being hinged to'the housing to permit it to be swung into open or closed position; The

illustrated hinge construction comprises lugs S struck up from a downwardly extending flange ll] of the cover, these lugs projecting through holes l2 in the rear of the housing 2 so that when the cover is open it may be removed'entirely from the casing, if desired, by pushing it rearwardly. At the front the cover is provided with a. second downwardly extending flange 14 which inserted through the holes 16 and I8 to permit the ready tiirr'iirig v of the screw 2-2 to move the lock 20' into or out of its locking relation to the casing 2 and depending flange Id of the cover 6'. The lock openings l6 and I8 are preferably covered by a shutter 24 swinging on'a screw 26 threaded into'the'flange 14 of the cover 6. The

, shutter 26 serves both to keep'the dust out of 'the casing 2 and to conceal the nature of the locking means. I

The: housing 2 and its-associated cover 6 are preferably elongated to furnish a foot rest of con:-

siderable longitudinal extent, for example; 16 to 18 inches or more, and there is preferably associated with the housing footoperated means for operating the circuit-closing mechanism, which is approximatelyof the longitudinal extent of the foot rest itself and is preferably at least of such extent that it may be engaged and operated by the foot when placed anywhere beneath the foot rest. This is important, it will be seen, inthe case of a holdup, to avoid the necessity for the one being held up moving laterally to any considerable extent to get his foot into position to engage the foot bar,a movement which might be attended with fatal consequences. In the illustrative preferred embodiment of the invention, the rod or bar 28, which is adapted to be engaged by the foot to operate the switch, is preferably round to insure its adapting itself readily to the movements of the foot and is connected at its ends to the arms 30' of two bellcrank levers which are carried upon pivots 32 each extending between two depending ears 35 of a bracket 36 attached by screws to the under side of the casing 2. The other arms 33 of the bellcrank levers extend through openings in the base'of'the brackets 36 and through openings in the bottom of the casing 2 into the inside of the casing 2 where they are connected by a rod 56' wardthe front of the casing Z'and thus hold the.

foot bar 28 in its depressed position. To retain the rod in its forward position and the foot bar 28 in its depressed position against unintentional movement by accidental contact of the toe of the foot with the foot bar 28, a detent or retaining means is provided. The illustrated detent, as hereinabove pointed out, preferably comprises, as a characteristic feature, a single element which performs three different functions, namely,- it acts as a part of the detent, it serves, when the detent is released, to aid in accelerating the movement of the parts toward circuit-closing position, and it constitutes a part of the means for locking the parts in circuit-closing position.

The illustrated detent further comprises a pin 50 which is screwed into the rod 36 and has a rounded head 52 which provides sufficient engagement with the bevelled wall of an opening 54 in the-spring member 56 so that when the parts are in the position shown in Figure 5 it will require substantial pressure upward on the foot bar 28 to cause the rounded head 52 of the pin '50 to develop a sufficient downward component of force,

as it presses against the bevelled wall of the opening 54 in the spring 5'5 to move the spring downward to a point where it will release the head 52 of the pin 50' and allow the bellcrank to rock from its open switch position to its closed,

switch position.

. The spring 56 is so tensioned that it tends constantly to press upward and it is so shaped that it has a portion 58 bent at substantially a 45 angle to the main part of the spring, this portion 58 extending between a slot 60 and the opening 54. As the pin rides over the edge of the opening 54, when the operator presses up on the foot bar 28, it comesinto engagement with the portion 58 of the spring 55, which is inclined, as shown, at a substantially 45 angle to the main part of the spring, and the upward pressure of the spring,

therefore, provides a horizontal component of force that tends to accelerate the rocking movement of the bellcran ks.

The net effect of this is that when theoperator is pressing up on the fo'ot'bar 28 the resistance of the detent to the ready movement of the bar causes him to increase the pressure until the detent is overcome, when the sudden release, together with the action of the horizontal component of force of the spring, effects a quick rocking of the bellcranks from one position to the other coupled with the moving of the mercury switches hereinafter to be described from open to closed position.

This relationship of the parts insures definite operation of the switch. When the operator presses up on the foot lever he will feel no substantial movement of the foot lever until the detent lets go, when the push that he is exerting on the foot lever will be of such an amount that he must necessarily follow through. It is thus impossible to operate the switch in such a manner that it will be left at an intermediate position in its movement from open position to closed po sition.

It Will be noted that the amount of movement of the switch lever necessary to move the detent from its retaining position to its let-go position is comparatively small but that the parts are so shaped that the detent has considerable holding force which has two advantages, first it prevents accidental operation of the switch and, secondly, it makes the operator build up the pressure on the foot bar 28 sufliciently to overcome this holding force, with the result that when the detent does let go the push on the foot bar insures complete operation.

The mercury switches themselves,there being preferably two, as in the prior construction, to render assurance doubly sure,-are mounted upon a novel carrier intended to insure greater tilting movement than in the case of the switches of the prior construction. As shown in Figures i and 5, the carrier 62 for the mercury switch 6 1 is of generally triangular shape and is pivoted at 66 near that apex of the triangle which is opposite the base to which the mercury switch is attached.

In the illustrative embodiment of the invention the carrier 62 is shown as forked to embrace a bracket 68 having a bearing to receive the pin or pivot 66 about which the carrier oscillates. The two mercury switch carriers andtheir brackets are located adjacent to the ends of the rod 40 and that one of the fork members of each carrier which is immediately adjacent to the end of the rod 40 is provided with a slot Hi to receive a pin 12 which may be formed as an extension of a screw-threaded bolt 74 threaded into the end of the rod 40 and serving as a means for connecting the rod 40 to the vertical arm of the bellcrank 38, the nut 16 being screwed upon said bolt '54 for this purpose.

It will be seen that when the mercury switch carrier 62 is being moved from one position to the other by the engagement of the pin '82, carried by the vertical bellcrank arm 38, the mercury switch carrier is being operated as a thirdclass lever, the movement of the load being a multiple of the movement of the power. It will also be seen that the arrangement of the parts is somewhat analogous to that of an inverted toggle in which the pivot 32 is the end pivot of one link of the toggle, the pivot 66 is the end pivot of the other link of the toggle, and the pin and slot connection 10, i2 constitutes the knee joint, the slot being a necessary provision since the end pivots are stationary.

By locating the pin 12 nearer to or farther away from the pivot 66, the angular movement of the mercury switch for a given movement of the bellcrank may be increased or decreased. In the illustrative embodiment of the invention the parts are preferably so arranged that the angular movement of the mercury switch carrier about its pivot is through an angle of substantially 74 which, as illustrated, will tilt the mercury switch from a position in which it is inclined at an angle of 37 to the horizontal, an inclination suficient to insure the mercury remaining at the end of the switch remote from the circuit terminals into a second position in which it is also inclined to the horizontal at an angle of 37 but with the circuit terminal end now in the lowermost position so that the mercury is caused by gravity to move to and maintain itself in circuit-closing relation to the circuit terminals.

The mercruy switch 64 may be of any of the'ordinary commercial types. The illustrated switch comprises an elongated glass tube 15 attached by a clamp TI to the base of the triangular carrier 62 so that its length is substantially perpendicular to a radius extending from the axis about which the carrier oscillates through the middle of the tube. Two circuit terminals '58 and 88 enter the tube through the base 82 and their ends, as shown, extend a suflicient distance into the tube to provide substantial contact surface for the mercury 84.

To provide for adjustment of the detent pin 52 with respect to the spring 56 and also with respect to the opening 54 in the spring 56, the vertical arm 38 of the bellcrank lever is provided with a horizontal oiTset 86 to receive a vertical stop screw 38 threaded therethrough. The stop screw 88 is adapted to strike against the bottom of the casing Z and limit the forward movement of the vertical arm 38 of the bellcrank in the casing. A set nut 90 is provided to lock the stop screw 88 in its adjusted position.

It will be obvious that by adjustment of the stop screw 88 the amount of movement required to move the detent into its let-go position may be varied and to some extent the amount of force required.

As in the case of the alarm switch of the prior application hereinabove identified, the switch herein described and illustrated is intended to be employed in an alarm circuit that is under constant electrical supervision to insure that everything will operate properly, this supervision being preferably effected by having the electrical parts located in a normally closed circuit through which a small supervisory current is constantly flowing, the flow of the current being maintained at a low level by resistance in the circuit so located that it will be short-circuited when any alarm switch in the circuit is operated, thus permitting an increase of current in the circuit sufficient to operate the alarm devices. The electrical supervision, as shown in Figs. 4 and 5, extends to those parts of the circuit terminals which are outside the mercury tube which, as a practical matter, is as far as is necessary.

A convenient arrangement of the resistance for maintaining the supervisory current at the proper level is to have it at the end of a line in which the alarm switches are arranged in parallel. The casing 2 is preferably so constructed that the resistance may be enclosed within that one of the alarm switch mechanisms which is nearest the end of the line.

A suitable circuit arrangement is illustrated diagrammatically in Fig. 6 where the resistance 92,preferablyof such construction and dimensions as to be insertable in the casing 2, in the space at the front shown in Fig. 4, is arranged to bridge two terminals 94 and 96 at the end of the line. The current for operating the alarms and forsupervision comes from any suitable source to switches and back to the binding post H4 and from there to the terminal I I6 of the other mercury switch and back to the post 9 to which the resistance 92 is connected.

Current coming in, for example, through the binding post 93 goes through the terminals I04 and I68, back to the post 96, through the resistance 92, post 9 3, wire lit to the terminal H6, then through the terminal H2 back to the binding post M19 or negative side of the circuit So long, therefore, as the resistance 92 is in the circuit the current coming in through binding post 98 and leaving through the binding post H30 will. be maintained at the proper supervisory level which is below the level necessary to operate the alarm apparatus but is sufficient to maintain trouble alarms inoperative.

If the mercury bridges either the terminals I04, H2, or the terminals I08, H6, or both simultaneously, as happens when this switch is operated, then connection is-made directly between wire [02 leaving binding post 98 and wire H leaving binding post Hi9, which short circuits the resistance thus permitting a flow of current through the alarm circuit controlled by these switches of suificient intensity tooperate the alarm signals.

To insure that the operation of the alarm switch shall be substantially noiseless, felt pads l l8, surrounding the rod G5, are interposed between the rod and the spring 56. Felt pads I20 fitting about the vertical arms 38 of the bellcrank lever' and held in position against. the bottom of the casing 2 by pins l22 serve, as in the prior conthe casing by the movement of the parts and atthe same time shut out from the outside whatever sounds originate in the casing from the movements of the parts.

Felt pads E25 also surround the foot bar 28'and serve both as sound-deadening cushions and as stops for the foot bar 28.

Although it has been suggested above that a convenient arrangement of the resistance for maintaining the supervisory current at theproper level is to have it at the end of a line in which the alarm switches are arranged in parallel, it will be understood that each alarm switch casing may be provided with a resistance controlling a separate indicator on the control panel thus providing for supervision of the individual switches. As shown in Figure l of the drawings, each one of the switch boxes is preferably provided with space and attachments for mounting the current superrising resistance 92 therein.

What we claim as new is:

' 1'.- A-hold-up alarm switch comprising, in comb'in atioriga mercury tube circuit closer, a carrier therefor pivoted to tilt said mercury tube between circuit breaking and circuit closing positions, a manually operated lever, connections between an arm of said manually operated lever and said carrier whereby a small angular movement of said manually operated lever effects a much larger angular movement of said carrier and resilient means for retaining said lever in its open circuit position, said retaining means having a retaining portion and an accelerating portion so located in relation to each other that an initial movement of said lever, constituting a relatively small part of the total movement thereof, releases said lever and brings it into the field of operation of said accelerating portion of said retainingmeans. a

2'. A hold-up alarm switch comprising, in com bination, circuit closing means movable between circuit breaking and circuit making position, a manually operated'lever connected to said circuit closing means toeifect the movement thereof between said two positions and a resilient detent constructed to hold said lever yieldably in open circuit position and substantially stationarycam surface so shaped. that the resilience of saiddetent is applied to said cam to accelerate and complete the manually initiated circuit-closing movement of said lever.

3. A hold-up alarm switch comprising, in combination, a circuit closer movable between circuit breaking and circuit closing positions, a manually operated lever, a detent for said lever arranged to v prevent movement thereof through a relatively small part of its total are of movement under force applied thereto below a predetermined level but to release said lever for free movement throughout the remainder of its are when force above a predetermined level has been applied thereto, and multiplying connections between said circuit closer and said lever whereby a small angular movement of said lever effects movement of said circuit closer between its circuit breaking andlcircuit closing positions, said detent being so shaped as to operate after its detaining .action has been overcome to accelerate and complete the manuallyinitiated movement of saidlever. to its circuit-closing limit of movement.

4. In a hold-up alarm switch, a mercury tube circuit closer, a carrier therefor pivoted to tilt said mercury tube between circuit breaking and circuit closin positions, a manually operated lever and multiplying connections between said lever and said carrier, and a detent comprising a pin carried by said lever, a spring having a pinengaging-recessfor holding said lever'in circuit breaking position and having a second recess for holding said lever in circuit closing position and a bearing surface between said recesses acting, when said detent lets go, to accelerate circuit closing movement of said lever.

JOHN H. DERBY. ADOLPI-l M. FROST. 

